Effect of meal size on myocardial oxygen requirements: Implications for postmyocardial infarction diet

Abstract

The validity of the assumption that eating a small meal places less postprandial demands on the circulatory system than eating a large meal was examined in eight healthy volunteers. Five meal sizes that ranged from 15 to 75% of daily energy requirements were fed. There was a significant correlation between meal size (in percentage of daily caloric requirements) and peak percentage change in cardiac index (p < 0.001) and stroke volume (p < 0.05) (echocardiography); heart rate (p < 0.001); an index of myocardial oxygen consumption (heart rate x mean blood pressure) (p < 0.01); and whole body oxygen consumption (p < 0.001). There was no significant correlation between meal size and peak percentage change in systolic and diastolic blood pressure. The duration of hemodynamic and metabolic changes that followed medium and large meals (≥ 35% of daily energy needs) exceeded smaller meals (≤ 25% of energy needs). These results may have implications in the management of patients with ischemic heart disease.